Leaders of the militant anti-pubco group - the GMB Pub Revolution - are set to meet new pubs minister John Healey next week, according to the union.
The meeting is due to take place before the GMB's parliamentary lobby day in Westminster on Tuesday.
Later that day, Healey is also expected to attend a Question Time style event being held in Parliament by the All-Party Save the Pub group and CAMRA.
During the GMB's lobby day, the 100 members of the union's parliamentary group have been invited to hear from GMB licensee members about their experiences.
Paul Maloney, GMB national secretary, said: "GMB considers that the average tied lessee is being overcharged by pubcos by around £12,000 per annum, after higher 'wet rents' and lower 'dry rents' are factored into the equation.
"GMB members on this lobby day will want to know why the regulators and legislators have to date refused to remedy this problem."
The lobby day follows 20 meetings for pubco tenants on the GMB pub revolution national roadshow tour that took place over the last month. The union is also planning another series of meetings in marginal seats in the run up to the general election.
The GMB has also threatened to hold a ballot for strike action among its licensee members.
However, earlier this week MPs on the Business Innovation and Skills committee warned against this.
"We advise against lessees deliberately breaking their tie contracts as part of a campaign for its removal," the committee's follow-up report on pubcos said.