"None of Ellerston Capital nor any of its shareholders or any of their associates hold a direct interest in the shares disclosed in this form," Kelly wrote.
"We attach our notice of becoming a substantial holder in respect of Fletcher Building."
Ellerston's 5.13 per cent stake amounted to 35,786,9434 ordinary shares, the notice showed.
Comment has been sought from Fletcher this morning on the big stand but not yet received.
Once any business buys more than 5 per cent of a company, a notice must be lodged with the stock exchange.
But whether Ellerston has bought on behalf of giant Australian business Wesfarmers remains unknown.
On Friday, Fletcher rejected speculation about Wesfarmers, which owns the Bunnings and Kmart businesses here.
"Fletcher Building noted today reports from various media outlets, stating that Wesfarmers has been accumulating Fletcher Building shares and now holds 3 per cent to 4 per cent of its shares," Fletcher said last week.
"The company has no knowledge of Wesfarmers owning Fletcher Building shares, therefore it can neither confirm nor deny the report," it said.
Fletcher shares were closing on Friday's NZX close around $6.34, a big rise on the $5.84 they had been at earlier last week.
If Ellerston bought at the low of $5.84 a share, it could have paid around NZ$208.9m.
Fletcher is dual-listed on the ASX and NZX.
Ellerston's ordinary shares come with voting rights, giving the business which controls the stake some say in the troubled Fletcher Building business, which said earlier this year it expected to lose nearly $1b in operating revenue from difficult construction jobs in New Zealand.