Underworld figure George Alex is expected to appear before the royal commission into trade union corruption after a summons was issued.

Underworld figure George Alex has been summoned to appear before the trade union royal commission and is expected to face the inquiry next week.

Mr Alex, who was recently granted bail on charges of making threats against people, has been named during the commission’s inquiries into the Construction, Forestry, Mining and Energy Union (CFMEU).

One witness to the commission, union whistleblower Brian Fitzpatrick, said he received a death threat from a fellow CFMEU official after complaining about the union’s alleged favourable treatment of labour hire companies linked to Mr Alex.

CFMEU NSW state secretary Brian Parker has also been called to appear before the commission.

Mr Fitzpatrick has alleged Mr Parker, whose nickname is “Sparkles” socialised with Mr Alex, including at a barbecue at his house with Melbourne underworld identity Mick Gatto.

Mr Fitzpatrick also said Mr Parker took no action over the alleged death threat when it was reported to him.

The commission has heard Mr Alex was involved in “phoenixing” labour hire companies – letting one company collapse without paying worker entitlements and transferring its assets into a new company.

The CFMEU has endorsed enterprise bargaining agreements with companies run by Mr Alex.

Mr Parker has rejected Mr Fitzpatrick’s allegations, issuing a statement in January in which he said he had no personal or social relationship with Mr Alex.

Mr Alex,43, was released on $50,000 bail on September 5 on the condition he go into a psychiatric facility for assessment.