Barratt Homes Yorkshire wants to build as many as 100 homes where the bowling greens, tennis and netball courts used to be on the former Reckitt-owned playing field in Chamberlain Road.
What is left of the site would house two adult and two mini-rugby pitches and changing rooms, with the developers also donating funds towards changing facilities at Pelican Park about a mile away.
However, campaigners want to keep the green space and are concerned that the rest of the field will eventually be lost to housing. There are about 1,200 names on a petition being organised by subpostmaster Serji Singh.
In a letter to Hull Council's planning department formally objecting to the proposals, Mr Bloom said developers had "put together a very glittery package making it look attractive to the general public, but closer inspection shows that the sports facilities they are proposing to build would actually be rather exclusive".
The UK Independence Party MEP added: "I understand Barratts are a profit-making company and it is perfectly proper for them to hold their view. But the astonishing removal of pro bono sports fields in the last 25 years must stop."
The Humber Playing Fields Association's chairman, Dave Craker, called for more assurances.
He said: "I can't see how they are going to fit the pitches, changing facilities and car parking in the designated area. The road they are proposing will cut into the pitch width. However we do need sport back as soon as possible."
The development is backed by Sport England and Hull FC, which says the plans are a "superb" way to redevelop the land. Barratt Homes said the proposals bring back into use an area which has been out of bounds to the public since 2006, and they represent "the most pragmatic solution to get it back into sporting and community use".