The ongoing drama surrounding the enforcement of US online gambling laws continued this past week, with credit card giant MasterCard reportedly blocking transactions on bets, leaving customers stranded.

The move took many by surprise given that implementation of the 2006 Unlawful Internet Gambling Enforcement Act, which effectively banned Internet gambling in the United States, had been delayed until June 1, 2010.

Implementation of the ban was originally supposed to be completed in December 2009.

It is rumored that rival credit card company Visa has also begun to crackdown on betting-related transactions. If so, the moves would suggest that credit card and payment companies are gearing up for implementation of the UIGEA, which bans companies from facilitating Internet gambling.

Mastercard's reported move came as the US Second Circuit Court of Appeals upheld a contempt order for refusal to comply with a grand jury subpoena against two companies owned by Canadian Douglas Rennick, who stands accused of processing more than $350 million for online gambling companies, and also faces charges in connection with bank fraud and money laundering.

These latest developments will no doubt prove good news for online payment methods such as NETeller, Neovia and Moneybookers, who will be sure benefit if customers turn their back on the credit card companies as expected.