Solih challenged President Islam Karimov in the 1991 presidential polls.
He has lived in exile since 1993 after a government crackdown on the opposition. He was also tried in absentia on charges of extremism and sentenced to a lengthy prison term in 1999. Independent human rights groups have said charges were politically motivated.
Current Uzbek legislation bans a candidate who has not lived inside the country for 10 consecutive years prior to the election run for the top post.
Erk did not explain how Solih plans to run under these circumstances.