Labour has called on the SNP to vote against Conservative plans to amend the law on fox hunting in England and Wales on Wednesday.
Ministers have put forward changes to the Hunting Act, to bring England and Wales in line with Scotland on using dogs to flush out foxes to be shot.
Labour plans to oppose the proposed changes in the Commons on Wednesday but the way the 56 SNP MPs vote could prove crucial to the outcome.
In a letter to the SNP's Westminster leader Angus Robertson, Labour frontbenchers Ian Murray and Maria Eagle called for SNP support.
SNP MPs do not usually vote on matters which do not affect Scotland, but a spokesman said the party would examine the details of the Government's proposals before deciding how to proceed.