Organisers behind the Rio Games have apologised to spectators who are having to endure queuing in long lines to get access to the Olympic Park on the first full day of the Olympics.
Organising committee spokesman Mario Andrada said that "we obviously need to upgrade" the systems, and have asked security to speed up bag checks.
On Saturday, he said: "We apologise to everyone who is standing in the sun in lines outside the venues... we need to fix this in the next couple of hours."
There have also been reports of official buses getting lost, and Mr Andrada said that organisers would check to see if drivers had been trained sufficiently.
But, he said: "We don't have major structural problems with transport."
Team GB diver Tom Daley tweeted a picture of his family ahead of his first event at the Rio Games.
Posting a selfie with his mother Debbie, partner Dustin Lance Black and other members of his family, he said: "So nice to have my family here to support me. Their support enabled me to get to where I am today. Forever grateful."
The 2012 bronze medallist is to compete in the Men's Synchronized 10m platform on Monday.
So nice to have my family here to support me. Their support enabled me to get to where I am today. Forever grateful❤ https://t.co/zzxTGetBTY
On Friday night, he posted a picture of himself with other members of Team GB ahead of the opening ceremony.
The proceedings saw a joyful celebration of Brazilian diversity and Carnival traditions married with a serious environmental message.Read the full story ›
The Olympic flame has been lit in the Maracana stadium, marking the official opening of the Rio Olympics.
Celebrated Brazilian runner Vanderlei Cordeiro de Lima carried the flame the final steps to the cauldron.
Michel Temer, Brazil's interim-president, has opened the Olympic Games, but was loudly jeered by some in the audience.
He spoke only briefly before declaring the Games open, initiating a fireworks display.
Mr Temer became the country's acting president after Dilma Rousseff was suspended awaiting a trial by the Senate.
Ms Rousseff did not attend the ceremony.
The refugee team, representing the 65 million displaced people around the world, have entered the Maracana stadium.
The team of 10 athletes was greeted with huge applause from onlookers.
The Rio Olympics is the first time a refugee team has competed in the Games
Team GB have taken to the Maracana stadium in Rio, led in by tennis champion Andy Murray.
Wearing red, white and blue, the squad soaked up the carnival atmosphere, with some taking selfies while all waved to the crowds.
"Who else got goosebumps", they asked in a Tweet.
The athletes of the 207 teams competing in the 2016 summer Olympics have made their appearance in the Maracana stadium.
As is traditional, Greece, the home of the Olympics, came in first, their flag carried for the first time by a female athlete.
In keeping with the environmental theme, each team is to be led out by a rider on a bicycle.
Amid the music and celebration, Brazil's opening ceremony has also included a sombre warning on climate change.
The serious segment began by examining the concentration of carbon dioxide on the planet.
It included the voice of British actress Judi Dench, who read an English translation of Carlos Drummond de Andrade’s poem, 'A Flor e a Náusea'.
The opening ceremony to the 2016 Olympic Games has got under way, lighting up the Maracana stadium in Rio de Janeiro.
The spectacular ceremony, which has so far retraced the history of Brazil and included dancing, capoeira displays and a performance of 'The Girl From Ipanema' - has as its themes were world peace and the environment.