The Manly Sea Eagles rugby league club has directly implored Malcolm Turnbull to abandon plans to banish lottery-betting sites from Australia, including the club's major sponsor, Lottoland.

In a letter to the Prime Minister, Sea Eagles chairman Scott Penn and chief executive Lyall Gorman made a plea for the government to reconsider its new legislation banning so-called "synthetic lottery" sites, which let Australians bet on the outcomes of foreign lotteries without having to buy a ticket in any draw.

Lottoland is a sponsor of the Manly Sea Eagles.

Lottoland, the Gibraltar-based online gambling site that has attracted controversy around the world, is a "premier sponsor" of the Manly Warringah Sea Eagles, and has contributed more than $1 million in funding to the club in the past two years.

"At a national level, you may be aware that Lottoland Australia will contribute over $30 million this year to a range of organisations like ours," the club's letter said, "so you can see why we are concerned that the proposed ban on online lottery betting will have a serious financial impact on our organisation, our members, our supporters and our wider communities."