The Mayor of New York City has offered $500,000 (£312,000) from his personal fortune towards the push for marriage equality in Maine, Minnesota and Washington.

Mayor Michael Bloomberg announced a political spending push last week. He said he planned to spend more than $10 million (£625,000), on promoting moderate candidates, and supporting equal marriage, the Associated Press reported.

He pledged $325,000 (£203,000), to groups pushing to uphold equal marriage law in the state of Washington, and to legalise it in Maine.

A further $125,000 (£78,000), was pledged, by Mr Bloomberg, towards efforts to oppose a constitutional amendment to strengthen the definition of marriage as between one man and one woman, in the state of Minnesota.

Earlier this month, the billionaire businessman-turned-politician pledged $250,000 (£155,430) to the campaign that is fighting to keep equal marriage in the US state of Maryland.

Back in July, Mr Bloomberg announced that more than 8,000 gay couples had married since the law came into action – one tenth of all marriages in the city in the year previous, and said that legalising equal marriage in the state had boosted the economy by $259 million (£161 million).

A year prior to that, he officiated the wedding ceremony of John Feinblatt, his chief policy advisor, and Jonathan Mintz, the city’s commissioner for consumer affairs, who had been together for 14 years.

A long-time advocator of equal marriage, Mr Bloomberg was part of a group of seventy mayors who joined together in January, with a view to increasing the pressure on President Barack Obama and to achieve full support of equal marriage rights nationwide.