A statement from the NCVO said that the two organisations had begun consulting with their respective members and had set up a dedicated website where members and staff could express views and pose questions about the merger proposal.
In an email to members, Ben Kernighan, deputy chief executive of the NCVO, said: "The new organisation will be a unifying voice for a large, diverse and collectively powerful sector. It’s important that this new organisation is shaped by the views and experiences of those on the ground."
Justin Davis Smith, chief executive of Volunteering England, said: "We want to make sure that the new, merged organisation lives up to the aspirations of all our members and stakeholders, and gathers strength from our combined efforts. This new website is a way to raise issues, ask questions and help create an even more powerful voice of volunteering."
Members are also being encouraged to take to Twitter using the hashtag #VE&NCVO to follow developments.
Kernighan, Davis Smith and Sir Stuart Etherington, chief executive of the NCVO, are to meet members around the country over the coming months.
Meetings will take place with the North West England Volunteering Development Council on 15 August, the South West EVDC on 2 October, Greater London Volunteering on 24 October, the National EVDC and National Network of Volunteer Involving Agencies on 12 November and the Eastern EVDC on 3 December. Other meetings are yet to be confirmed.
The merger proposal was first announced in June.